Human PLD structures enable drug design and characterization of isoenzyme selectivity

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• Phospholipase D (PLD) enzymes are crucial phosphodiesterases producing phosphatidic acid (PA), a vital second messenger and building block.
• Previous structural data from bacterial PLD lacked sufficient homology for understanding human PLD (hPLD) functions.

Purpose of the Study:

• To determine the first crystal structures of human PLD1 and PLD2 catalytic domains.
• To identify novel structural elements and functional differences between prokaryotic and eukaryotic PLDs.
• To elucidate inhibitor binding modes and isoenzyme selectivity determinants for drug discovery.

Main Methods:

• X-ray crystallography to obtain structures of hPLD1 and hPLD2 catalytic domains.
• Structure-based mutation studies.
• Co-crystallization with dual and isoform-selective inhibitors.

Main Results:

• First crystal structures of hPLD1 and hPLD2 catalytic domains are presented.
• Novel structural features differentiating eukaryotic from prokaryotic PLDs were identified.
• Binding modes of various inhibitors were elucidated, revealing key determinants for isoenzyme selectivity.

Conclusions:

• The determined structures provide a molecular basis for hPLD1 and hPLD2 functions.
• Findings facilitate structure-based drug discovery for therapeutically relevant PLD inhibitors.
• This work enhances understanding of PLD isoenzyme selectivity and function.